Improving efficiencies by modulating the central metal ion in porphyrin-oligothiophene-mediated P3HT/PCBM organic solar cells

The power conversion efficiencies of poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric acid methyl ester (P3HT/PCBM) bulk heterojunction organic solar cells were increased through the addition of small amounts (1–10%) of metalloporphyrin-oligothiophene conjugates. The effectiveness of these porphyrin additives was found to increase in the order free-base < Co < Zn < Ni < Cu, with the efficiency being enhanced by up to 17% for the terthiophene-substituted Cu(II)-porphyrin, pointing to an important effect of the metal center.